It is known to provide protection for the drain of a flush basin, particularly a urinal, to prevent blockages by objects which have been thrown into the basin such as cigarette butts or other objects. Commonly, this protection is provided by inserting a perforated plate made from metal or plastic. A disadvantage of the usual perforated plate is that water which flows into the basin during flushing can move the plate from its protective location so that objects thrown into the basin can still enter the drain and block it. A further disadvantage exists with certain kinds of dirt traps which are provided with a container for receiving a fragrant, vaporizable or soluble body of material which is provided for disinfection and improving the smell. In such devices, the dirt trap must be removed and a separate container removed in order to permit the insertion of a new body of fragrant material.